Place the digestive biscuits into a sealable sandwich bag. Push all the air out and seal the bag. Crush the biscuits with a rolling pin into fine crumbs.
Melt the butter in a large saucepan. Tip the biscuit crumbs into the butter and mix well until thoroughly combined. Press the buttery crumbs into the bottom of a 23cm/9in springform or loose-bottomed tin. Chill in the fridge while you make the topping.
Fold the vanilla extract into the mascarpone.
Spread the cream cheese mixture over the biscuit base and smooth the top with a palette knife or spatula. Cover with cling film and chill in the fridge for at least four hours.
When ready to serve, sprinkle Joe & Seph's Salted Caramel Popcorn on top and drizzle with Joe & Seph's Salted Caramel Sauce. Release the catch of the springform tin carefully, then slice and serve chilled.